1. Field of the Invention
The present invention relates to a driving game machine which is played by the player to simulate the driving of an automobile and which displays on a display monitor a three-dimensional image that varies depending on the manner in which the simulated automobile is driven by the player.
2. Description of the Related Art
There have been in widespread use driving game machines that are played by the player who is seated in a cockpit equipped with a steering wheel, an accelerator pedal, a brake pedal, etc., similar to the driver's seat of an actual automobile. while seeing a three-dimensional image displayed on a display monitor, the player operates the steering wheel, the accelerator pedal, the brake pedal, etc. to drive a simulated automobile on the display monitor. The display monitor displays, on a displayed road, the automobile driven by the player, a rival automobile or automobiles competing for a driving game, and general automobiles existing as obstacles. The automobile driven by the player will be referred to as the player's automobile, and the rival and general automobiles as other automobiles.
In a driving game played on the driving game machine, it is necessary to display when the player's automobile collides with another automobile, and the other automobiles are required to understand their positional relation to each other and move based on that understanding. Consequently, the positional relation between the player's automobile and the other automobiles and also between the other automobiles has to be determined each time the image displayed on the display monitor is refreshed. The positional relation between those displayed automobiles can relatively easily be determined if the displayed road along which the automobiles runs is flat and straight.
Usually, however, the displayed road is a three-dimensional road which has curves and ups and downs, because the player would lose interest in the flat and straight road in the driving game. The positional relation between the displayed automobiles on such a three-dimensional road has to be determined after the displayed positions of the player's and other automobiles are calculated in a three-dimensional coordinate system. Therefore, it will take a long period of time to determine the positional relation between the displayed automobiles on the three-dimensional road. It is laborious and time-consuming to produce a program which is capable of determining the positional relation on a real-time basis each time the displayed image is refreshed, resulting in a reduction in the efficiency of development of driving game machines.